Buzz
By Locke Hughes
Midway through the initial plank sequence in barre class, you’re drenched as if you’ve taken a dip in a pool, while your friend remains completely dry. Or perhaps you’re someone who can power through a treadmill workout without breaking a sweat. What’s the reason behind this?
To begin, let’s explore the science behind sweating. “Perspiration is an essential mechanism that helps regulate body temperature,” says David M. Pariser, M.D., a dermatologist and founding member of the International Hyperhidrosis Society.
When your body begins to overheat, the nervous system activates sweat glands to produce perspiration. As the sweat evaporates from your skin, it carries away excess heat, cooling you down. (Consider how cold your skin feels when wet after a shower—the evaporation of water cools your body. Sweat functions similarly to lower your temperature as it evaporates.)
Sweating does not detoxify your body, according to Pariser. “Over 99 percent of sweat is water, with minimal traces of electrolytes like salt.” Although a small quantity of toxins can exit the body through sweat, the primary detoxification process happens in the liver, kidneys, and lungs—not through the skin.
How Much Sweating Is Excessive?
Almost any level of sweating is normal. “There’s significant variation in how much people sweat, and most fall within a normal range,” Pariser states. “Similar to height, there’s an average sweat rate—some people sweat more, while others sweat less.”
If you’re always slightly damp, there’s no need to worry. “Everyone sweats a baseline amount continuously,” Pariser notes. Most individuals sweat more noticeably during exercise, in hot environments, or in stressful, awkward, or uncomfortable situations. (Think of an awkward first date!)
However, excessive sweating, particularly in specific areas, could signal a medical condition called hyperhidrosis, which affects 2 percent of the U.S. population, Pariser explains. One type, focal hyperhidrosis, may be hereditary and causes sweating in localized areas (typically underarms, feet, hands, or face). The other type may result from another illness (like diabetes or hyperthyroidism), menopause, or certain medications. If you experience excessive sweating, consult a doctor to determine if it’s hyperhidrosis.
How Fitness Levels Influence Sweating in Unexpected Ways
If you’ve ruled out medical issues and still find yourself sweating excessively, it might just mean you’re in great shape. (Yes!) Research over the years has shown that endurance athletes tend to start sweating earlier and produce more sweat than those who aren’t as physically trained.
“The fitter you are, the more effectively your body sweats,” says Tony Musto, Ph.D., a fitness director and exercise physiologist at the University of Miami. This is beneficial because sweating helps regulate body temperature, allowing you to exercise at higher intensities for longer periods. (You want to avoid reaching a core temperature of 104 degrees, which can lead to heat illness or heat stroke.)
This doesn’t mean inactive individuals won’t sweat. There’s a link between sweating and VO2 max, a measure of cardiovascular fitness and aerobic endurance. Studies indicate that long-distance runners with higher VO2 max levels tend to start sweating sooner and produce more sweat.
It gets a bit complex: When performing the same activity (like running at 5 mph on a treadmill), a less fit person might hit their VO2 max faster than a fit person, causing them to sweat sooner and more profusely, even though the fit person sweats more efficiently overall. This is because the less fit individual might be working at 80 percent of their VO2 max, while the fit person is only at 50 percent.
Conversely, if both a fit and unfit person are exercising at the same relative intensity (e.g., 60 percent of their VO2 max), the fit individual running at 8 mph will begin sweating sooner and produce more sweat than the unfit person running at 5 mph, according to Musto. This also clarifies why trained runners sweat more than untrained individuals in the study—they can run faster and harder, generating more body heat and perspiration.
Additional Influences
To add another layer of complexity, several other factors affect how much you sweat.
1. Gender
If you’ve ever entered or passed by a men’s locker room, this finding won’t surprise you. In a study, trained and untrained men and women cycled on stationary bikes for an hour in an 86-degree room. Researchers analyzed the number of active sweat glands and the overall sweat rates of each participant.
The findings revealed that fit men sweated the most, particularly during high-intensity exercise. Fit women ranked second in sweat production, while sedentary women perspired the least among all groups. Despite women having more sweat glands than men, each gland produces less sweat, as the researchers noted.
2. Body Mass
Another factor contributing to the study’s results: “Men are generally heavier, have greater muscle mass, and generate more heat during exercise than women,” Musto explains. Additional research indicates that individuals with a higher body mass index (BMI) tend to sweat more.
3. Coffee
A steaming cup of coffee can raise your body temperature, potentially increasing sweat production. However, if coffee’s diuretic effect occurs before exercising and you visit the bathroom beforehand, you might actually sweat less, according to Musto. This could lead to a subpar workout, so it’s essential to drink plenty of water alongside coffee to stay hydrated. The American Council on Exercise suggests consuming 17 to 20 ounces of water two to three hours before exercising and seven to 10 ounces every 10 to 20 minutes during a workout.
4. Alcohol
Have you ever noticed your face flushing after a few drinks? Alcohol speeds up your heart rate and expands blood vessels near the skin, increasing blood flow to the surface. This raises your body temperature, potentially causing more sweating. Contrary to what hot yoga enthusiasts might think, you can’t simply “sweat out” alcohol after a night of drinking: Only about 5 percent of alcohol exits the body through sweat, breath, and urine, while the remaining 95 percent is processed by the liver.
5. Spicy Foods
Consuming spicy foods also elevates your body temperature, prompting your body to sweat as a cooling mechanism, Musto explains. If you notice excessive sweating while eating, it might indicate Frey’s syndrome, or gustatory sweating. Individuals with Frey’s syndrome sweat profusely at the mere thought or taste of food, even something as mild as ice cream. Consult a doctor if you suspect this could be a concern.
6. Hot Weather
This might seem obvious, but hotter weather increases your body temperature, causing your heart rate and blood flow to rise as your body tries to cool down, Musto explains. Humid conditions make it worse: With more moisture in the air, sweat evaporates slower, hindering the body’s cooling process.
The Takeaway
Numerous factors influence how much someone sweats, and nearly all levels of perspiration can be considered normal. Plus, the fitter you are, the more you sweat, which helps your body sustain activities like running, lifting, or cycling for longer periods. However, if you’re constantly sweating excessively, particularly in one area, it might indicate a rare condition called hyperhidrosis. Consult a doctor if you’re worried.
